Answer
Trip Tracker continues to exist and work on the Apps10 track — there's no immediate forced migration away from it. Separately, using Aurena (accessed through a normal mobile browser) for expense reporting requires no special mobile device setup at all: there's a dedicated 'Quick Expense Reporter' screen in Aurena, along with the standard 'New Expense' assistant, both usable directly in a browser on a mobile device without any additional configuration. A dedicated native Aurena mobile app was still in development and not yet confirmed for the Apps10 track at the time this was raised — check current release notes for the latest status.